Crushing and drying apparatus



Se t. 26, 1967 F. RASMUSSEN 3,343,800 CRUSHING AND DRYING APPARATUSFiled April 2, 1965 1771 FIG 2 l'" I up.

INVENTOR.

ATTORNEYS l fs f rms? United States Patent 3,343,800 CRUSHHNG AND DRYINGAPPARATUS Frits Rasmussen, Copenhagen-Valby, Denmark, assignor to F. L.Smidth & Co., New York, N.Y., a corporation of Delaware Filed Apr. 2,1965, Ser. No. 445,014 Claims priority, application Great Britain, Apr.29, 1964, 17,813/64 Claims. (Cl. 241-47) ABSTRACT OF THE DISCLOSUREApparatus for simultaneously crushing and drying moist material whichincludes means for introducing hot gas into a casing and crushing meansinside the casing in the path of the hot gas. The crushing means iscomprised of impactors for crushing the material against impact membersand has a gas by-pass defined between a casing and the impact memberswhich places the gas in heat exchange relationship with the impactmembers to dry any moist material which may accumulate on these members.

This invention relates to apparatus for crushing mineral materialcontaining moisture as delivered, for example, from a quarry, and isconcerned more particularly with a novel apparatus for both crushing anddrying moist material. In the apparatus of the invention, the crushingoperation is performed by impact action and the material is dried by hotgas passed through the zone where the crushing is being carried on. Theconstruction of the apparatus is such that the efiiciency of thecrushing means does not decrease as the rate of supply of the materialto the apparatus increases and the apparatus is, accordingly, effectivefor the production of dried crushed material at a high output rate.

Impact crushers, in which the material is crushed by being struck by oneor more rotary impactors and thrown against impact surfaces, are wellknown and hot gas has been introduced through the bottom of the casingof such a crusher to flow upwardly through the impact zone to dry thematerial. In a crusher of this type, the hot gas passes out through thetop opening of the casing, through which the material is introduced, andcarries with it entrained crushed material.

In such impact crushers with hot gas flow, as heretofore constructed, ithas been found that the efiiciency of the apparatus is impaired, if themoist material is fed into the crusher casing at too rapid a rate. Thereasons for this action are that, first, the hot gas is unable topenetrate a large mass of moist material undergoing crushing, so thatthe material in the interior of the mass is not properly dried, and,second, the moist material clings to the impact surfaces and formscoatings thereon which decrease the effectiveness of the impact action.

The present invention is, accordingly, directed to an apparatus forcrushing and drying moist material, which overcomes the objections tothe prior crushers above described and can be operated at a higheroutput rate without loss of elficiency. In the new apparatus, the impactmembers are so disposed within the crusher casing as to cooperate withthe casing walls to form one or more by-passes, through which hot gasmay travel from the bottom opening of the casing to the opening at thetop. Part of the gas entering the casing flows up through the crushingzone to take part in the drying of the material therein, while theremainder of the gas flowing through the by-passes continually gives upheat to the impact members, so that they dry material in contacttherewith and the formation of coatings on the members is avoided. Atthe top of the casing, the gas, which has passed through the crushingzone and has carried upwardly sufliciently fine crushed material iscombined with the by-pass gas and the latter is effective to dry theentrained crushed material leaving the casing.

For a better understanding of the invention, reference may be made tothe accompany drawing, in which:

FIG. 1 is a vertical sectional view on the line 11 of FIG. 2 of one formof the new crushing apparatus;

FIG. 2 is a vertical sectional view on the line 22 of FIG. 1; and

FIG. 3 is a view similar to FIG. 1 showing a different form of theapparatus.

The crushing apparatus shown in FIGS. 1 and 2 includes a metallic casing10 which is reinforced by plates 11. The casing has a top opening 12,from which leads a duct 13, and an opening 14 at its bottom to whichleads a duct 15.

A pair of impactors 16a, 16b are mounted in the lower part of the casingand each impactor comprises a shaft 17 having radial flanges 18 on whichhammers 19 are pivotally mounted on rods 20. The impactors are rotatedin the direction of the arrows (FIG. 1) and material struck by thehammers is thrown against impact members within the casing.

The members, against which material is thrown by the hammers of theimpactor 16a, include plates 21, 22 carried by a frame 23 pivotallymounted at 24 on opposite casing Walls. The frame 23 is held in properposition by a rod 25 which extends through an opening in the casing walland is encircled by a spring 26 hearing at one end against a nut 27 onthe end of the rod and at the other against the casing wall. Below theframe 23 carrying the impact members 21, 22, there is mounted a thirdimpact plate 28 carried by a frame 29 pivotally mounted on the casingwall. A bar 30 is attached to the frame 29 and extends through anopening in the casing wall, outside which it is attached to the outerend of a safety pin 31, the inner end of which is attached to the casingwall. The pin is so made that it will break and release the frame, whenthe pin is subjected to an excessive stress as a result of a heavyimpact against the plate 28.

The plates 21, 22, and 28 cooperate with the wall of the casing todefine a by-pass 32 between the casing wall and the impactor 16a and theplates are so disposed in relation to the casing wall that the by-passdecreases in cross-sectional area in an upward direction. Thecrosssectional area of the by-pass may be further controlled by means ofa throttle plate 33 mounted on the frame 23 between plate 21 and thecasing wall.

The impactor 16b and the impact members associated therewith are of thesame construction as the impactor 16:1 and its impactor members and thecorresponding parts are designated by the same reference characters withthe prime mark added. The impact plates 21', 22', and 2S cooperate withthe casing wall to form a by-pass 32' between the wall and the impactor16b and the bypass decreases in cross-sectional area in an upwarddirection. Flow through the by-pass 32' may be controlled by a throttleplate 33 mounted on the frame 23.

Grids 34 are disposed below the respective impactors 16a, 16b and thegrids lie close to the path of travel of the outer ends of the hammers19, 19 of the impactors, so that material lodging upon a grid will bethrown by the hammers of the associated impactor toward the other.

In the operation of the crushing and drying apparatus shown in FIG. 1,the moist material to be crushed is introduced through the duct 14 andfalls upon the impactors by which it is thrown against the impactmembers. The members lie outside the downward projection of the opening13 at the top of the casing so that material to be crushed may dropbetween the plates 22, 22' without being intercepted thereby and thehorizontal offsetting of plates 21 and 22 and of plates 21 and 22 allowsmaterial, which may have accidentally entered the by-passes, to fall tothe impactors 16a, 16b. During the crushing action, hot gas isintroduced into the casing through the duct and flows upward through thecasing and out through the opening 12 and duct 13. Part of the hot gaspasses up between the impact plates 28, 28' and thus through thecrushing zone, while the remainder flows through the bypasses 32, 32'defined by the casing walls and the adjacent impact plates. The gas,which flows through the crushing zone, entrains crushed material and isjoined at the top of the casing by the gas which has traveled throughthe by-passes. The by-pass gas heats the impact plates so that moistmaterial tending to adhere thereto will be dried and will either notadhere or will be knocked free by material thrown against the plates bythe impactors. Material not struck by the hammers but passing throughthe grids falls into the path of the gases flowing into the casing andis ordinarily entrained and carried through the casing either betweenthe impactors or through the by-passes.

The gas with entrained material which travels through the duct 13 ispassed to a separator in which the crushed dried material is separatedfrom the gas. Material which passes between the impactors or through thegrids and is not entrained by the hot gas, is collected and combinedwith the separated dried material discharged through the duct 14 oradded to the material to be crushed.

The crushing apparatus shown in FIG. 3 includes a casing 35 having a topopening 36, from which leads a duct 37, and a bottom opening 38, towhich leads a duct 39. A rotary impactor 16 of the same construction asthe impactors 16a, 16b is mounted within the casing and it acts to throwmaterial against impact members comprising horizontally spaced impactplates 4%, 41 mounted on a frame 42 pivotally mounted on the casingwall. The frame is held in position by a rod 43 attached to the frameand extending through the casing wall and the exposed part of the rod isencircled by a spring 44 bearing at one end against the casing wall and,at the other, against a nut 45 on the rod. The impact members alsocomprise a plate 46 mounted on a frame 47 pivotally mounted on thecasing and held in place by a bar 48 attached to the frame and extendingthrough an opening in the casing wall. The exposed part of the bar isattached to the outer end of a safety pin 49, the inner end of which issecured to the casing. The pin will break and release the frame if thelatter is subjected to an excessive stress.

The plates 40, 41, and 46 cooperate with the wall of the casing to forma by-pass 50 which decreases in crosssectional area in an upwarddirection. Gas flow through the by-pass may be controlled by a throttleplate 51 mounted on the frame 42.

Fixed impact members 52 are mounted on the opposite side of the impactor16' from the frames 42, 47 and the plates 40, 41 and 46 carried thereby.The members 52 cooperate with the casing walls to form a bypass 53 whichdecreases in cross-sectional area in an upward direction. As in theconstruction shown in FIG. 1, the impact members above the impactor lieoutside the downward projection of the opening 36 and thus do notinterfere with the free fall of material introduced into the casingthrough the opening 36.

In the operation of the form of the crushing apparatus shown in FIG. 3,the moist material to be crushed is introduced into the casing throughthe opening 36 and falls between the fixed impact members 52 and theplates 40 and 41 to the impactor 16. Hot gas enters the casing from theduct 39 through the opening 38 and part of the gas travels through theby-passes 5t 53, while the remainder passes upward through the crushingzone. Material reduced to the proper size is entrained in the gaspassing between the plates 40, 41, and 46 and the plates 52 and carriedout of the casing through the opening 36. The hot gas traveling throughthe by-passes heats the impact members so that the moist material willnot adhere to the surfaces of the members and thus reduce the efiiciencyof the crushing operation.

I claim:

1. An apparatus for simultaneously crushing and drying moist material,comprising a casing having openings at its top and bottom, means forintroducing hot gas into the casing through the bottom opening, meansfor introducing material to be crushed into the casing and forconducting gas and entrained crushed material from the casing throughthe top opening, and crushing means inside the casing in the path of gasflowing upwardly through the casing, the crushing means includingimpactors for crushing material against impact members and the impactmembers adjacent to but spaced from the casing side walls andco-operating therewith to define at least one by-pass open at its bottomto receive part of the hot gas introduced through the bottom opening ofthe apparatus with the gas flowing upwardly through the by-pass in heatexchange relationship with the impact members to dry material in contacttherewith and the top of the by-pass opening adjacent the top opening ofthe apparatus so that gas from the bypass combines with the gas andentrained material to dry the entrained material.

2. The apparatus of claim 1, in which the impact members partly definingthe bypass are spaced successively closer to the casing wall to decreasethe cross-sectional area of the bypass toward the top opening of thecasing.

3. The apparatus of claim 1, in which the impact members are disposedoutside the downward projection of the boundary of the top opening ofthe casing.

4. The apparatus of claim 1, in which two of the impact members partlydefining the bypass and disposed adjacent to the top opening are spacedhorizontally for escape from the bypass of material entering the upperend of the bypass.

5. The apparatus of claim 1, in which means for regulating the flow ofgas through the by-pass are mounted inside the casing.

6. The apparatus of claim 5, in which the regulating means comprise athrottle plate mounted on an impact member and reducing thecross-sectional area of the bypass.

7. The apparatus of claim 1, in which the impact members cooperate withopposite side walls of the casing to define a pair of by-passes with thecrushing means between them.

8. The apparatus of claim 1, in which the crushing means include atleast one impactor mounted for rotation inside the casing adjacent tothe bottom opening and impact members on opposite sides of the impactorcooperating with opposite side walls of the casing to define by-passesfor gas around the crushing means.

9. The apparatus of claim 7, in which a grid is disposed within thecasing below the crushing means.

10. The apparatus of claim 8 in which the crushing means includes twoimpactors mounted for rotation on substantially parallel horizontalaxes.

References Cited 5 1,027,964

UNITED STATES PATENTS 348,977

9/1896 'Bailly 24147 992483 4/1907 Du Pont 24165 X 385,600 6/1916Coleman 241-47 X 1/1929 Wood 241-80X 6/1930 Lykken 241189 X 11/1949Kessler 241-189 X FOREIGN PATENTS 10 WILLIAM W. DYER, JR., PrimaryExaminer.

R. I. ZLOTNIK, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,343,800 September 26, 1967 Frits Rasmussen It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 5, after line 12, insert 3,058,676 10/1962 Hermann -241-186Signed and sealed this 24th day of September 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

1. AN APPARATUS FOR SIMULTANEOUSLY CRUSHING AND DRYING MOIST MATERIAL, COMPRISING A CASING HAVING OPENINGS AT ITS TOP AND BOTTOM, MEANS FOR INTRODUCING HOT GAS INTO THE CASING THROUGH THE BOTTOM OPENING, MEANS FOR INTRODUCING MATERIAL TO BE CRUSHED INTO THE CASING AND FOR CONDUCTING GAS AND ENTRAINED CRUSHED MATERIAL FROM THE CASING THROUGH THE TOP OPENING, AND CRUSHING MEANS INSIDE THE CASING IN THE PATH OF GAS FLOWING UPWARDLY THROUGH THE CASING, THE CRUSHING MEANS INCLUDING IMPACTORS FOR CRUSHING MATERIAL AGAINST IMPACT MEMBERS AND THE IMPACT MEMBERS ADJACENT TO BUT SPACED FROM THE CASING SIDE WALLS AND CO-OPERATING THEREWITH TO DEFINE AT LEAST ONE BY-PASS OPEN AT ITS BOTTOM TO RECEIVE PART OF THE HOT GAS INTRODUCED THROUGH THE BOTTOM OPENING OF THE APPARATUS WITH THE GAS FLOWING UPWARDLY THROUGH THE BY-PASS IN HEAT EXCHANGE RELATIONSHIP WITH THE IMPACT MEMBERS TO DRY MATERIAL IN CONTACT THEREWITH AND THE TOP OF THE BY-PASS OPENING ADJACENT THE TOP OPENING OF THE APPARATUS SO THAT GAS FROM THE BY-PASS COMBINES WITH THE GAS AND ENTRAINED MATERIAL TO DRY THE ENTRAINED MATERIAL. 